Safety lock for food freezers or refrigerators

ABSTRACT

A SAFETY LOCK FOR LOCKING THE DOOR STRUCTURE OF A FOOD FREEZER OR REFRIGERATOR TO PREVENT UNAUTHORIZED ACCESS TO THE FOOD COMPARTMENT WHICH FUNCTIONS IN COMBINATION WITH A MAGNETIC TYPE DOOR SEAL SUCH THAT THE LATCH OPERATES TO LOCK THE DOOR. THE DOOR LOCK IS PROVIDED WITH THERMOSTATIC MEANS WHICH PERMITS THE DOOR TO BE LOCKED AND UNLOCKED IN THE ORDINARY MANNER BY MEANS OF A KEY OPERATED LOCKING BOLT WHEN THE FREEZER IS BEING USED FOR THE PRESERVATION OF FOOD AND WHICH THERMOSTATIC MEANS RENDERS THE LOCK INOPERATIVE IN A FAIL-SAFE MANNER TO PREVENT LOCKING THE DOOR IN THE EVENT THE FREEZER IS DISCONNECTED FROM ITS CURRENT SUPPLY.

Dec. 14, 197] J MANN ETAL 3,626,712

SAFETY LOOK FOR FOOD FREEZERS OR REFRIGERATORS Filed Sept. 21, 1970 5 V I5NVEN'TORS LeonardJMam BY Thomasfifi Maul/5 ATTORNEY United States Patent 3,626,712 SAFETY LOCK FOR FOOD FREEZERS 0R REFRIGERATORS Leonard J. Mann, Kettering, and Thomas H. Fogt, Carrollton, Ohio, assignors to General Motors Corporation, Detroit, Mich.

Filed Sept. 21, 1970, Ser. No. 73,880 Int. Cl. F25d 29/00 U.S. Cl. 62--161 3 Claims ABSTRACT OF THE DISCLOSURE A safety lock for locking the door structure of a food freezer or refrigerator to prevent unauthorized access to the food compartment which functions in combination with a magnetic type door seal such that the latch operates to lock the door. The door lock is provided with thermostatic means which permits the door to be locked and unlocked in the ordinary manner by means of a key operated locking bolt when the freezer is being used for the preservation of food and which thermostatic means renders the lock inoperative in a fail-safe manner to prevent locking the door in the event the freezer is disconnected from its current supply.

This invention relates to food freezer and refrigerator door locks and particularly to safety locks for hinge doors of food freezers or the like.

It is the purpose of the present invention to eliminate the possibility of having the door of an electrically disconnected freezer from being relocked after the door has been initially unlocked. Such a possibility is particularly hazardous in the case of a child entering the compartment of a discarded or abandoned freezer cabinet and being trapped therein by locking of the compartment door either accidentally or by a second child on the outside turning the key. Initially freezer doors of the type disclosed in U.S. Pat. 2,764,874, issued Oct. 2, 1956 were provided with latch mechanisms for locking the door structure tightly closed against the freezer cabinet structure to seal the food compartment access opening. With the advent of vinyl magnetic seals incorporating a bar magnet such seals have replaced the latch mechanisms as the sole means to maintain the door in the closed position because of the magnetic attraction between the bar magnet and the metallic cabinet face in accordance with well known practice. An example of one type of sealing strip magnet is disclosed in U.S. Pat. No. 3,055,193, issued Sept. 25, 1962. Under certain conditions, such as with food freezer type refrigerators, it is common to have a built in door lock mechanism to protect the frozen food investment. With such a mechanism it is desirable to provide an electrically controlled fail-safe device such that if the electricity is oh the device will prevent a person from locking the door once it has been unlocked.

To this end an object of the invention is to provide a locking device for the food compartment door of a refrigerator freezer cabinet which will have a safety interlock means on the lock which prevents the locking bolt from being operated to its locked position when the freezer is without electrical power.

A further object of the invention is to provide a freezer door lock with an approved electrically controlled thermostatic means which permits the door to be locked and unlocked in the ordinary manner by rotating a key operated cylinder on the door when the freezer is being used for the preservation of foods and which thermostatic means renders the lock inoperative upon the loss of electric current by preventing the key from locking the door closed once the locking cylinder has been rotated to its unlocked position.

3,626,712 Patented Dec. 14, 1971 "ice Carrying out the foregoing objects, it is a further and more specific object of our invention to associate an electrically heated bimetallic resiliently biased thermostat with the door locking mechanism of a freezer cabinet or the like, the heater of which is connected to a detachable electrical circuit leading from the source of electrical current supply to the freezer and is continually energized as long as the freezer is employed for preserving food to permit the locking mechanism to lock and unlock the door, said door locking mechanism including a locking bolt having a segmented gear portion forming a ratchet and the bimetallic thermostat having a lock bar type pawl carried thereby such that the gear portion in the locking bolt is positioned to be engaged by the lock bar and which heater is deenergized upon or in response to disconnecting the detachable extension cord plug of the freezer from the current supply causing the bimetallic thermostat to bias the lock bar into the path of rotation of the locking bolt rendering the locking mechanism inoperative insofar as relocking the door closed is concerned once the lock has been initially unlocked. I

Further objects and advantages will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of the invention is clearly shown.

In the drawings:

FIG. 1 is a perspective view showing a household food freezer incorporating the invention;

FIG. 2 is an exploded view of the freezer lock;

FIG. 3 is a fragmentary sectional view of the door of a freezer cabinet taken along lines 33 of FIG. 1;

FIG. 4 is a fragmentary sectional view taken on line 44 of FIG. 3 showing the lockbolt in plan with the lock bar out of the path of movement of the gear segment of the lock bolt;

FIG. 5 is a fragmentary sectional view taken on line 5-5 of FIG. 4 showing the bimetallic member in plan;

FIG. 6 is an enlarged detail of the engaging portions of the lock bar and segmental gear;

FIG. 7 is a diagrammatic showing of a detachable electric circuit associated with the freezer having the invention incorporated therein.

Referring to the drawing, for illustrating our invention, we show in FIG. 1 thereof a food freezer cabinet generally represented by the reference numeral 10. This freezer cabinet construction will be herein only briefly described and for a better understanding of its specific structure or character, reference is made to U.S. Pat. No. 3,403,534, issued Oct. 1, 1968. Freezer cabinet member 10, preferably although not necessarily, includes an outer inverted U-shaped metal shell 11, provided with a multifarious uninsulated front edge formation, such as disclosed for example in the U.S. Pat. No. 3,006,708, having walls, one of which being indicated at 12, forming sides of the cabinet member and a door jamb portion 13. While we show a somewhat recently developed upright freezer cabinet structure, our invention is not necessarily restricted to this particular type of cabinet construction and may include, for example, a horizontal chest-type food freezer or a refrigerator cabinet. A metal boxlike liner 14, having one side thereof open, is located in the cabinet outer shell 11 and forms walls of the food storage chamber 15 therein with the open side of the liner providing the chamber with an access opening. Any suitable or desirable insulating material (not shown) is disposed between walls of metal shell 11 and liner 14. An insulated door member or structure generally represented by the reference number 20 in FIG. 1 of the drawing, is hingedly mounted on cabinet 10 as at 21 for horizontal swinging movement relative thereto and abuts against the door jamb 13 to normally close the access opening of chamber 15. While the chamber 15 may be for the storage of foods above the freezing temperature the instant embodiment describes a frozen food storage or food freezing chamber maintained at a temperature well below 32 F. A machine compartment is provided in cabinet below chamber and is closed at its front by a removable panel or the like 23. This compartment houses the freezer translating device including a motor compressor unit sealed within a casing and a refrigerant condenser of a refrigerating system connected in closed refrigerant flow relationship with one another and with a refrigerant evaporator associated with chamber 15 for chilling air therein by the refrigerating effect produced thereby. Such a refrigerating system is well known, conventional in the art and is therefore not shown in the present disclosure.

Door in the present discosure comprises a sheet metal outer panel 26 (FIG. 2), an inner preferably molded plastic panel or the like 28 and a gasket 30 mounted on the door member and carried thereby for engagement with or having a junction with cabinet member 10. Gasket H 30 is a one piece rubber like element of special construction such as one type disclosed in US. Pat. 3,078,134 providing a vinyl seal containing a magnet which registers with and has magnetic attraction to the edge part of metal door jamb 13 of cabinet 10 to hold, without the aid of additional means such as a latch, door 20 in closed position thereagainst. This practice is common in the art as shown by the above mentioned patent and the novelty of the present disclosure is not based thereon.

As seen in the exploded view of FIG. 2, locking means for locking door structure 20 tightly closed against the freezer cabinet structure comprises a lock housing or frame structure for location within door 20 and which may be secured to edge panel 41 thereof in any suitable or desirable manner. The housing structure 40 includes two upright side walls 42, 43, end walls 44, 45 and an integral lower connecting wall 46 having an offset portion 47 (FIG. 3) defining an integral mounting block 48. The housing 40 has a cover member 50 which is seated in the housing 40 and is secured thereto by means of screws 51 threaded into tapped holes in integral boss portions 52, 53 formed on housing walls 44, 45.

A lock generally indicated at 56 extends through an opening 57 in the edge panel 41 of the outer door panel 26 such that outer head portion 58 of the lock 56 is disposed in abutting engagement with the surface of the edge panel 41. The lock 56 has a reduced casing portion 59 projecting through the opening 57 and into bore in the lock housing block 48. The lock 56 is secured to the door panel 41 by a clevis or bifurcated type spring retaining clip 61 which straddle the reduced casing 59 of the lock.

The lock 56 has a conventional rotatable key or locking cylinder 62 that is mounted in the lock casing 59, and which is controlled through a usual arrangement of pin tumblers and spring pressed drivers as disclosed for example in US. Pat. 2,097,407, issued Oct. 26, 1937. The inner housing end of the key cylinder 62 has a lock bolt 63 secured thereon by suitable means such as Phillips head screw 64. The lock bolt 63 includes an enlarged annular base plate portion 65 and an offset latch portion 66 for engaging a keeper 67 (FIG. 1) suitably mounted on the door jamb 13 of the freezer. Thus, when the lock bolt 63 is rotated in a 90 arc the latch portion 66 projects through a suitable slot 68 provided in flange 69 of the door edge panel 41 and is adapted to engage the keeper 67.

The present conventional door lock is highly desirable and practical particularly from the standpoint of being capable of locking the door against unauthorized access to the compartment. We, therefore desire to modify this type of lock mechanism to overcome the hazard of a child being trapped in a discarded freezer cabinet equipped with the lock of the present type. In accordance with our invention we have modified the lock mechanism disclosed for accomplishing the objects hereinbefore set forth by associating an electrically heating thermostatic means therewith. As seen in FIG. 5 this thermostatic means includes a U-shaped bimetallic leaf spring member 72 having a pair of parallel dissimilar length legs 73, 74 joined at one end by a cross portion 75. The free end of the shorter leg 73 is anchored to the housing 40 as by suitable means such as screw fastener 76 upon a recessed side wall 77 of the housing. The longer leg 74 of the bimetal member 72 is positioned to extend along one side of and parallel with the lock bolt 63 such that it is free to move within the housing.

The free end of the leg 74 is reverse bent into a hookshaped portion 78 to slidably receive an elongated lock bar 80 therein and in the preferred form the lock bar 80 has a substantially square cross section with its longitudinal axis aligned substantially parallel with the principal axis of the locking cylinder 62. The lock bar 80 extends transversely of the leg 74 such that its longer protruding left-hand end 81 is received in a conforming slot 84 formed in the block portion 48 of the housing 40 and an opposed complementary slot 86 in the raised portion 87 in the housing cover 50 receives the shorter right-hand end 82 of the lock bar 80. It will be appreciated that because the lock bar 80 travels in a linear path within the slots 84, 86 it is necessary that the bar be free to move radially within the U-shaped hook of the leg 74 to prevent binding thereof. In this connection the slots 84, 86 have their open ends beveled as indicated at 89 in FIG. 4 for slot 86 to insure free movement of the lock bar 80 therein.

The leg 74 of bimetallic member 72 overlies an electric resistance wire resistor or heater element 88 and is positioned in heat exchange relationship therewith such that the high expansion side of the leg 74 faces the heater 8 8 for receiving the heat therefrom. The lock bar 80 is resiliently biased to the right, as viewed in FIG. 4 for lateral movement in slots 84, 86 towards the path of rotational movement of the lock bolt 63. The lock bar 89 is normally moved to the left away from the path of the lock bolt 63 as bimetal leg 74 is deflected to the left under the influence of radiant heat emitted from the heater 88 impinging upon leg 74 as current is passed therethrough. It will be noted that the leg 73 is partially shielded by recessed wall from the radiant heat of the heater 88 and therefore is not operatively heated.

The heater 88 forms a part of a detachable electric circuit connected to a source of electric current supply and extending therefrom to an electrically generated refrigerant translating unit such, for example, as a motor-compressor condenser unit of a closed refrigerating system associated with the freezer cabinet. This circuit comprises a detachable extension electric cord Supplied with a freezer and pluggable into a wall or the like receptacle connected to a source of electric current for rendering the refrigerating system of the cabinet operative. The closed freezer system also includes a refrigerant evaporator (not shown) for cooling the interior of the food storage compartment of the freezer cabinet and suitable conduits interconnecting the refrigerant translating unit with the evaporator.

Referring now to FIG. 7 of the drawings, the elements in the electric circuit include a refrigerant translating unit such as a sealed unit 90 containing an electric motor and a refrigerant compressor driven thereby. One wire 91 of the detachable cord (not shown) disconnectable circuit has a lead wire 92. leadig to one side of the winding of the electric motor in unit 90. The other side of the motor winding of unit 90 is connected by wire 93 to a thermo static switch 94 and to the other wire 95 of the detachable plug of the extension cord of the freezer. The thermostatic switch 94 controls starting and stopping of unit 90 in response to temperatures within the food storage compartment of the freezer as is common in the art. The disconnectable circuit also comprises the resistance winding of electric heater 88 connected across wires 91 and 95 by branch wires 96 and 97. Heater 88 is continuously energized when the circuit, with unit 90 therein, is connected to a source of electric current supply for rendering the freezer system operative.

Heat dissipated by the heater 88 causes bimetal leg 74 to bow to the left into the position shown in FIG. 4 to hold the lock bar 80 out of the path of movement of lock bolt 63. In the preferred form the heater 88 is a 9,000 ohm resistor having a rating of about 15 watts enabling the heater 88 to increase the temperature of the bimetallic thermostat leg 74 by approximately 50 F. under a usage of an electric current of approximately 13 milliamps. The bimetallic leg 74 is responsive to varying ambient temperatures in addition to the heating provided by the heater 88. In order to make the operation of the bimetallic thermostat independent of the former influence compensation is provided by mounting the U-shaped bimetallic member by means of its shorter leg 73. The leg 73, having the same thermal deflection characteristics as the leg 74, causes the hook portion 78 of the leg 74 to remain in a relatively fixed position and so maintain a constant relationship between the lock bar '80 and lock bolt 63 independent of ambient changes. Consequently, changes in ambient temperature which result in similar changes in the temperature in the two legs 73 and 74 do not effect the operation of the thermostat so that the device is ambient temperature compensated.

The key 100 comprises a Yale portion (not shown) for releasing the lock tumblers and a finger-gripping portion 102. The locking bolt 63 is atfixed to the inner end of the key cylinder 62 and operates with the prevent rotary locked movement of the cylinder 62 from the unlocked position to the locked position when the freezer unit is in its unplugged condition. The locking bolt 63 and latch 66 are shown in the locked and latched position in dashed lines indicated at 66b in FIG. 4. The lock mechanism includes the lock bar 80 slidable within the slots 84, 86 and engageable with a sector or segmented gear portion 104 on the periphery of the base plate 65 of the lock bolt 63 having a plurality of teeth, 106a-106 in the instant embodiment, to prevent clockwise movement, as viewed in FIG. 4, of the lock cylinder 62 and the locking bolt '63. When used with the key the lock bolt can rotate in either clockwise or counterclockwise direction when the detachable cord is connected to a source of electric current. It will be noted in FIG. 6 that the gear teeth 106a through 106] are arranged such that the points of the adjacent teeth intercept an arc of approximately 10. By virtue of providing a plurality of teeth 106a-106 it will be appreciated that when the lock mechanism is assembled and installed on a production basis on different freezer models it is not necessary that the positioning of the locking bolt 63 and keeper 67 be in exact alignment to insure that the lock bar 80 will engage a single gear tooth. As long as the lock bar 80 engages any one of the segmental gear teeth the locking bolt will be prevented from returning to its locked position.

If the detachable cord is disconnected from the source of electric curret for any reason the bimetallic leg 74 will move lock bar 80 into contact with the locking bolt 63. This occurs because disconnecting the circuit causes electric heater 88 to be deenergized whereupon leg 74' will cool to ambient or room temperature and will be resiliently biased to the right as viewed in FIG. 4 and lock bar 80 may be caused to mesh with the sector gear 104 depending upon the location of the lock bolt 63'. It will be noted that if the locking bolt 63 is in its unlatched vertical full line position of FIG. 4, the lock bar 80 will not initially engage the sector gear 104 portion of the bolt. As the locking bolt is rotated in a clockwise direction as viewed in FIG. 4, however, the face of initial tooth 106a will engage the lock bar 80 to prevent the movement of the latch 66 beyond the location indicated by dashed lines 66a to positively insure against engagement with its keeper 67.

If the locking bolt 63 is in its latched position indicated by dashed lines 66b the tooth 106 will initially engage the lock bar 80, as shown by the lock bar full line position in FIG. 6.

When the key cylinder 62 and locking bolt 63 are turned manually by the key in a counterclockwise direction, commencing from the position of 66b (FIG. 4) of the latch the segmented gear 104 will displace the lock bar 80 to the left so as to ride over the lock bar 80. This results because the teeth 106 are each formed to present substantially right angle located gear faces, indicated at 108 and 110 in FIG, 6, to conform with adjacent faces of the square-shaped lock bar 80. Continued counterclockwise movement of the bolt 63 causes the lock bar 80 to be displaced by the sector gear 104 because upright gear faces 108 are operative to slide the lock bar 80 to the left (shown in the dotted line position illustrated in FIG. 6) a suflicient distance such that the peaks of the gear teeth 106 may clear the lock bar. If the operation attempts to rotate the locking bolt 63 in a clockwise locking direction, however, the lock bar 80 assumes the solid lines spring biased position illustrated in FIG. 6 whereby it is immovably positioned between gear teeth 106 of the gear segment. The particular gear tooth face 110 contacting lock bar 80 thereupon exerts a substantially vertical force on the lock bar 80 to prevent its movement in grooves 84, 86 and thereby positively prevent clockwise or locking rotation of the lock bolt 63. Stated differently the lock bolt 63 in this condition can be turned in the unlocking direction, but not-in the locking direction.

Therefore, if the refrigerating system associated with the freezer cabinet is rendered inoperative for storing food or if an old freezer cabinet is to be discarded the disconnecting of the circuit from the source of electric current provides a positive means of preventing the locking of door 20 to the cabinet after the subsequent unlocking of the door as just described. Thus, if a child should enter the food compartment of the freezer after the subsequent unlocking of the compartment door 20 and the door then closes, the locking mechanism is inoperative and cannot be locked inadvertently or by a second child outside the freezer.

The magnetic type seal which causes a magnet in the seal to hold the door in the closed position is of the safety latch" type in accordance with Federal legislation on freezers wherein a push required on the inside of the door is of the order of 15 pounds to enable a child to easily open the door from within. Therefore the improvement particularly assists in eliminating the hazard of the likelihood of children becoming locked in freezer cabinets and losing their lives.

While the embodiment of the present invention as herein disclosed constitutes the preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. In a food freezer or the like, a cabinet structure having a compartment therein provided with an access opening and a door structure adapted to close same, a closed refrigerating system associated with said cabinet structure including a refrigerant evaporator for cooling the interior of said compartment and an electrically operated refrigerant translating unit, an electric circuit detachably connected to a source of electric current and leading therefrom to said unit, locking means for said door structure, said locking means including a rotatable member carried on the door having a key receiving slot therein, said rotatable member including a locking bolt rotatable to and from locked and unlocked positions adapted to engage a keeper on the cabinet, thermostatic means associated with said locking bolt responsive to disconnecting said detachable circuit from said power source of electric current arranged to prevent rotation of the said locking bolt from the unlocked position to the locked position, said thermostatic means including a bimetallic member including a section movable with respect to said locking bolt member, a movable lock bar carried by said section, a segmented gear portion on said locking bolt in position to be engaged by said lock bar, said bimetallic member being resiliently biased so as to move said locking bar in the path of rotation of said locking bolt segmented gear, electric heater means having a connection with said circuit for heating the high expansion side of said bimetallic member and normally maintaining said lock bar out of the path of said locking bolt segmented gear portion, said lock bar and said segmented gear portion operative when in engagement to permit unlocking rotation of said locking bolt member only.

2. In a food freezer or the like, a cabinet structure having a compartment therein provided with an access opening and a door structure adapted to close same, a closed refrigerating system associated with said cabinet structure including a refrigerant evaporator for cooling the interior of said compartment and an electrically operated refrigerant translating unit, an electric circuit detachably connected to a source of electric current and leading therefrom to said unit, locking means for said door structure, said locking means including a housing member carried on the door, an outer lock casing having lock cylinder rotatable to and from locked positions within said outer lock casing and having a key receiving slot in its front end, said lock cylinder having a locking bolt rotatable therewith having a latch portion adapted for engagement with a keeper on the cabinet, said locking bolt having an annular portion of relatively larger diameter than said lock casing in end engagement with the inner end of said locking cylinder, thermostatic means associated with said locking means responsive to disconnecting said detachable circuit from said power source of electric current arranged to prevent rotation of said locking bolt from the unlocked position to the locked position, said thermostatic means including a bimetallic member fixed to said housing including a section movable with respect to said outer casing member, a lock bar carried by said section, a segmented gear portion on said locking bolt annular portion, said lock bar slidable in groove means in said housing member, said bimetallic member being a leaf spring resiliently biased so as to move said locking bar into the path of rotation of said segmented gear, electric heater means having a connection with said circuit for heating said bimetallic member and normally maintaining said lock bar out of the path of said locking bolt segmented gear portion, said lock bar being rectangular in cross section and the gear teeth of said segmented gear conforming therewith such that when said lock bar is meshed with said gear teeth said lock bar is slidably movable to allow said lock bar to be displaced by said gear teeth and thereby permit unlocking rotation only of said locking cylinder.

3. In a food freezer or the like, a cabinet structure having a compartment therein provided with an access opening and a door structure adapted to close same, said door structure having an outer shell and a nested inner liner defining a hollow wall space therebetween into which insulation is placed, a closed refrigerating system associated with said cabinet structure including a refrigerant evaporator for cooling the interior of said compartment and an electrically operated refrigerant translating unit, an electric circuit detachably connected to a source of electric current and leading therefrom 8 to said unit, locking means for said door structure, said locking means comprising a lock housing fixed to the inner face of said door outer shell, a lock comprising an outer casing member extending through an opening in said door outer shell in an aligned bore located in a mounting block portion of said lock housing, a lock cylinder rotatable to and from locked and unlocked positions within said outer casing member, said locking cylinder having affixed thereto on its inner housing enclosed end a lock bolt for rotation therewith, said lock cylinder having a key receiving slot in its outer end therein and rotatable to and from locked and unlocked positions for rotating said locking bolt through a second opening in said door shell to engage a keeper on said cabinet, thermostatic means associated with said locking means responsive to disconnecting said detachable circuit from said power source of electrical current arranged to prevent rotation of the said cylinder from the unlocked position to the locked position, said thermostatic means including a resiliently biased bimetallic member being a U-shaped leaf spring providing substantially parallel first and second legs of unequal length joined together at one end of each leg, the other end of said first shorter leg being mounted to said lock housing and the other end of said second longer leg movable in a plane transverse to the principal axis of said locking cylinder adjacent the inner end thereof, said bimetallic member being positioned with its high expansion side facing said locking bolt, an elongated lock bar connected to said other end of said second leg for movement with respect to said housing and said second leg, said lock bar having its longitudinal axis aligned substantially parallel with the principal axis of said locking cylinder for movement of its end portions in opposed slots formed in said housing, said locking bolt having an annular portion and a keeper engaging latch portion, said annular portion being of relatively larger diameter than said lock casing and in fixed end engagement with the inner end of said locking cylinder, said annular portion having a segmented gear portion thereon located to be engaged by an intermediate portion of said lock bar, said second leg being resiliently biased so as to move said lock bar into the path of rotation of the teeth of said segmented gear portion, an electric heater having a connection with said circuit for heating said second leg and normally maintaining said loc-k bar out of engagement with said segmented gear, said circuit when detached from said source of electric current causing said second leg to move said lock bar into the path of said segmented gear portion, said lock bar and said segmented gear portion operative when in engagement to permit unlocking rotation only of said locking cylinder, said first and second legs operative so that changes in ambient air temperature produce similar changes in the temperature of said legs whereby said thermostatic means is ambient temperature compensated.

References Cited UNITED STATES PATENTS 7/1958 Sharpe 6216 X 3/1959 Miller 62267 x WILLIAM J. WYE, Primary Examiner 

